Low cost optical package

ABSTRACT

An optical package having a patterned submount, an optoelectronic device mounted to the patterned submount, a spacer affixed on one side to the patterned submount, the spacer having a bore hole therethrough wherein the optoelectronic device is positioned, and an optical element affixed to the spacer on a side opposite the patterned submount and covering the spacer bore hole. The patterned submount may be a circuit board. The optoelectronic device may be a VCSEL. The spacer may be affixed to the circuit board, for example, using an epoxy preform or an adhesive laminate. The spacer may, for example, be manufactured from a sheet of stainless steel or from a circuit board. The optical element may be, for example, a diffuser, a concave lens, a convex lens, a holographic element, polarizers, or diffraction gratings. The optical element may be affixed to the spacer using an epoxy preform or an adhesive laminate.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Prov. Pat. Appl. No.61/735,724, titled “Low Cost Optical Package,” filed Dec. 11, 2012,which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to optical packages. Particularly, thepresent disclosure relates to low cost optical packages foroptoelectronic dies, such as Vertical-Cavity Surface-Emitting Lasers(VCSELs), light emitting diodes (LEDs), or photodetectors.

BACKGROUND OF THE INVENTION

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

VCSELs have been offered commercially since the mid-1990s. One of thelargest applications for VCSELs has been in fiber optic communication,and they were initially offered in transistor outline (TO) packages,hermetically sealed. However, efforts have been made to make VCSELs morerobust in environments that vary in temperature and/or humidity so thata wider variety of packages can be used. In broadening the applicationof VCSELs to consumer applications, there is a need in the art forpackaging approaches that are both low cost and which also enable theeasy integration of various electrical and optical elements with theVCSEL.

BRIEF SUMMARY OF THE INVENTION

The following presents a simplified summary of one or more embodimentsof the present disclosure in order to provide a basic understanding ofsuch embodiments. This summary is not an extensive overview of allcontemplated embodiments, and is intended to neither identify key orcritical elements of all embodiments, nor delineate the scope of any orall embodiments.

The present disclosure, in one embodiment, relates to an optical packagehaving a patterned submount, an optoelectronic device mounted to thepatterned submount, a spacer affixed on one side to the patternedsubmount, the spacer having a bore hole therethrough wherein theoptoelectronic device is positioned, and an optical element affixed tothe spacer on a side opposite the patterned submount and covering thespacer bore hole. In one embodiment, the patterned submount may be acircuit board, such as a printed circuit board. The optoelectronicdevice may be a VCSEL. The spacer may be affixed to the circuit board,for example, using an epoxy preform or an adhesive laminate. The spacer,in one embodiment, may be manufactured from a sheet of stainless steel.In another embodiment, the spacer may be manufactured from a circuitboard. The optical element may be, for example, a diffuser, a concavelens, a convex lens, a holographic element, polarizers, or diffractiongratings. The optical element, such as a diffuser, may be affixed to thespacer using an epoxy preform or an adhesive laminate.

The present disclosure, in another embodiment, relates to an array ofoptical packages having a first circuit board panel comprising aplurality of VCSEL submounts each configured for mounting a VCSELthereto, a second circuit board panel including a plurality of boreholes therethrough, the second circuit board panel being shaped anddimensioned to align with the first circuit board panel such that theplurality of bore holes align with the plurality of VCSEL submounts, andan optical panel including a sheet of optic-altering material, theoptical panel being shaped and dimensioned to align with the secondcircuit board panel such that the sheet covers the plurality of boreholes. In one embodiment, the first circuit board panel may be a printedcircuit board. The second circuit board panel may be affixed, on a firstside thereof, to the first circuit board panel, and may be affixed, on asecond side thereof, to the optical panel. In one embodiment, the secondcircuit board panel may be coated on the first and second sides thereofwith an adhesive laminate for affixing the second circuit board panel tothe first circuit board panel and the optical panel by lamination. AVCSEL may be mounted to each of the plurality of VCSEL submounts. In oneembodiment, the optical panel comprises a sheet of light diffusingmaterial.

The present disclosure, in still another embodiment, relates to a methodof making an optical package. The method may involve attaching aplurality of VCSELs to a first circuit board panel comprising aplurality of VCSEL submounts, each configured for receiving a VCSEL. Asecond circuit board panel may be aligned with the first circuit boardpanel, the second circuit board panel having a plurality of bore holestherethrough and being aligned with the first circuit board panel suchthat the plurality of bore holes align with the plurality of mountedVCSELs. An optical panel may be aligned with the second circuit boardpanel, the optical panel having a sheet of optic-altering material andbeing aligned with the second circuit board panel such that the sheetcovers the plurality of bore holes. The method may also involvelaminating the first circuit board panel, second circuit board panel,and optical panel together. The method may further include dicing thelaminated panels into singular optical packages, each optical packagecomprising a VCSEL aligned with a bore hole and configured to emit alaser beam through the optic-altering material of the optical panel.

While multiple embodiments are disclosed, still other embodiments of thepresent disclosure will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. As will be realized, thevarious embodiments of the present disclosure are capable ofmodifications in various obvious aspects, all without departing from thespirit and scope of the present disclosure. Accordingly, the drawingsand detailed description are to be regarded as illustrative in natureand not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter that is regarded as formingthe various embodiments of the present disclosure, it is believed thatthe invention will be better understood from the following descriptiontaken in conjunction with the accompanying Figures, in which:

FIG. 1A is a schematic side view of an optical package according to anembodiment of the present disclosure.

FIG. 1B is a schematic top view of an optical package according to anembodiment of the present disclosure.

FIG. 2A is a schematic top view of a circuit board for an opticalpackage with mounted VCSEL according to an embodiment of the presentdisclosure.

FIG. 2B is a schematic bottom view of a circuit board for an opticalpackage according to an embodiment of the present disclosure.

FIG. 3A is a schematic top view of a circuit board illustratingsolder/bond pad patterns according to an embodiment of the presentdisclosure.

FIG. 3B is a schematic bottom view of a circuit board illustratingsolder/bond pad patterns according to an embodiment of the presentdisclosure.

FIG. 4A is a top view of a circuit board for an optical package withmounted VCSEL according to an embodiment of the present disclosure.

FIG. 4B is a bottom view of a circuit board for an optical packageaccording to an embodiment of the present disclosure.

FIG. 5A is a schematic top view of a spacer for an optical packageaccording to an embodiment of the present disclosure.

FIG. 5B is a schematic side view of a spacer for an optical packageaccording to an embodiment of the present disclosure.

FIG. 5C is a top view of a spacer for an optical package according to anembodiment of the present disclosure.

FIG. 6A is a top view of an optical package, without an optical elementlayer, according to an embodiment of the present disclosure.

FIG. 6B is a top view of an optical package, with a diffuser layer,according to an embodiment of the present disclosure.

FIG. 7A is a schematic exploded view of an optical package according toan embodiment of the present disclosure.

FIG. 7B is a schematic top view of an optical package according to anembodiment of the present disclosure.

FIG. 7C is a schematic bottom view of an optical package according to anembodiment of the present disclosure.

FIG. 8 is a flow chart of a method of making an optical packageaccording to an embodiment of the present disclosure.

FIG. 9A is a schematic exploded view of an array panel of opticalpackages according to an embodiment of the present disclosure.

FIG. 9B illustrates 3 separate panel layers of an array of opticalpackages according to an embodiment of the present disclosure.

FIG. 10A is a schematic top view of a wiring board or circuit boardpanel for an array of optical packages according to an embodiment of thepresent disclosure.

FIG. 10B is a close-up of a section of the wiring board or circuit boardpanel of FIG. 10A.

FIG. 11A is a top view of an optical package diced from an array ofoptical packages according to an embodiment of the present disclosure.

FIG. 11B is a bottom view of an optical package diced from an array ofoptical packages according to an embodiment of the present disclosure.

FIG. 11C is a side view of an optical package diced from an array ofoptical packages according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure relates to novel and advantageous opticalpackages. Particularly, the present disclosure relates to novel andadvantageous low cost optical packages for VCSELs. However, while thebelow description focuses mainly on packaging VCSELs, the apparatus andmethods described herein could also be applied to the packaging of otheroptical components, such as but not limited to, LEDs and photodetectors.While any VCSELs or other optical components may be utilized, examplesof the type of VCSELs that may be utilized with the optical packagesdescribed herein include those described in: U.S. Pat. No. RE41,738,titled “Red Light Laser”; U.S. Pat. No. 8,249,121, titled “Push-PullModulated Coupled Vertical-Cavity Surface-Emitting Lasers and Method”;U.S. Pat. No. 8,494,018, titled “Direct Modulated ModifiedVertical-Cavity Surface-Emitting Lasers and Method”; U.S. patentapplication Ser. No. 13/559,821, titled “Method and Apparatus IncludingImproved Vertical-Cavity Surface-Emitting Lasers,” filed Jul. 27, 2012;U.S. patent application Ser. No. 13/571,839, titled “Push-Pull ModulatedCoupled Vertical-Cavity Surface-Emitting Lasers and Method,” filed Aug.10, 2012; U.S. patent application Ser. No. 13/729,166, titled “Methodand Apparatus Including Movable-Mirror MEMS-Tuned Surface-EmittingLasers,” filed Dec. 28, 2012, each of which is hereby incorporated byreference herein in its entirety.

More particularly, the present disclosure describes a packaging approachthat provides a great deal of flexibility in integrating VCSELs inarrays with other types of electrical components or elements, such asbut not limited to, integrated circuits (ICs) and passive components,like resistors and capacitors, as well as with a variety of opticalcomponents or elements, including but not limited to, lenses, diffusers,and holographic elements. Optical elements, for example, may be alignedwith respect to a VCSEL component in the x-, y-, and z-directions. Thez-direction (i.e., the direction perpendicular to the VCSEL chip) can bea particular challenge as the distance between the VCSEL and the opticalelement should be well-controlled.

In general, an optical package according to the present disclosure,illustrated conceptually in FIGS. 1A and 1B, may generally involvemounting a VCSEL die or chip 102 (also referred to herein simply asVCSEL) or multiple VCSELs on a circuit board or patterned submount 104,such as a ceramic submount, creating a spacer layer 106, and mounting anoptical element 108 on top of the spacer layer. The circuit board orsubmount 104 can also be designed to incorporate many other components,including but not limited to, one or more ICs for driving the VCSEL(s),resistors, capacitors, amplifiers (e.g., if connected to aphotodetector), and/or electrical connectors. The circuit board orsubmount 104 can be designed or laid out to accept multiple VCSEL, LED,or photodetector die to create an array. Any suitably variety of boardmaterials may be utilized. In one particular embodiment, a circuit boardwith a copper core may be used to provide improved thermal conductivity.While illustrated conceptually as a square or rectangular board, as willbe illustrated later, the packages described herein may be configured inany suitable shape, such as circular, hexagonal or other polygonalshape, etc., and is not limited to being shaped as a square orrectangle.

In one embodiment, the VCSEL die 102 may be placed in direct contactwith the copper core, for example, by exposing the core and placing theVCSEL directly on top of the core or by creating copper filled vias thatwould lie under the VCSEL that connect to the core. The VCSEL 102 may beattached to the board 104 using any suitable means of attachment, suchas a conductive epoxy, or for better thermal conductivity, by using asolder. If a VCSEL has been built on a conducting substrate, thenplacing it in contact with metal on or in the board 104 can provide theelectrical contact to one side of the VCSEL's p-n junction. Contact tothe other side of the VCSEL's p-n junction may be provided to the VCSEL,for example, by wire bonding to bond pads on a top surface of the VCSELchip 102. Alternatively, both contacts to the VCSEL 102 may be accessedon a top surface of the VCSEL and can be wire bonded to the board 104.In such embodiments, the substrate side contact of the VCSEL maygenerally continue to serve as a thermal heat sink.

According to the present embodiment, in order to provide proper spacingfrom the VCSEL 102 to any optical element 108, a spacer 106 or spacerlayer can be created which can be operably coupled or otherwise attachedto the circuit board or submount 104. The spacer 106 may be made fromany suitable material, such as but not limited to, metal, ceramic, or aplastic material. The spacer 106 may be manufactured using anymanufacturing process or technique, and in some embodiments for example,the spacer may be molded or machined. The spacer 106 may be suitablycoupled, attached, or affixed to the circuit board or submount 102 usingany suitable means for attachment, such as but not limited to, using asolder or an epoxy 110. An epoxy could be dispensed, or could be anepoxy preform. An epoxy preform may provide a more controlled thicknessfor accurate control of the height of the spacer. The solder or epoxy110 thickness, plus the spacer 106 thickness may be designed to positionor hold an optical element 108 at a predetermined height above anemitting aperture of the VCSEL 102. This height, for example, couldrange from about 0.1 mm to several millimeters above the emittingaperture of the VCSEL 102. The desired height may vary from applicationto application. In one embodiment, the desired height may be determinedby the beam divergence of the VCSEL 102 and the design of any opticalelement 108 that is placed above the VCSEL. Many optical elementsrequire a spacing that is larger than that which is typically availablefrom conventional ceramic packages.

A variety of optical elements 108 may be utilized with or in the opticalpackages of the present disclosure. In one embodiment, for example, theoptical element 108 positioned on top of the spacer 106 may be a convexor concave lens, a diffuser, which spreads out the VCSEL beam 112, or aholographic element that could split or shape the VCSEL beam. Theoptical element 108 could also include elements, such as but not limitedto, polarizers or gratings that can bend the VCSEL beam or select aparticular wavelength.

Some of these optical elements could require alignment in the x- andy-directions relative to an optoelectronic die, such as a VCSEL, LED, orphotodetector. In one embodiment, this can be achieved by incorporatingalignment marks into the circuit board or submount 104 and the opticalelement 108. A standard vision system conventionally used in boardmanufacturing, for example, may be used to perform the alignment.

The optical element 108 may be attached to the spacer 106 using anysuitable means of attachment, such as but not limited to, using a solderor an epoxy 114. An epoxy could be dispensed, or could be an epoxypreform. Again, an epoxy preform may provide a more controlled thicknessfor accurate control of the height of the spacer. The optical element108 may be made of any suitable material and manufactured using anysuitable manufacturing process or technique. In one particularembodiment, the optical element 108 may be made of glass or plastic andcould be molded, machined, polished, and/or etched.

The assembly of the above described components may be performed usingany standard board manufacturing processes, such as pick and place ofthe components using automated systems with machine vision systems. Apanel of smaller circuit board-based packages can be assembledsimultaneously for additional efficiencies. In general, a panel ofcircuit boards may be populated with the optoelectronic die (e.g.,VCSEL, LED, photodetector), other ICs, passive electrical components,like resistors and LEDs, the spacer, and any optical element. Since thespacer and optical element can be attached after the placement and wirebonding of other components, wire bonding issues created by the presenceof a deep wall on a package may be avoided. A burn-in of the opticalelement(s) 108 while still attached to the board 104, may beimplemented. Even testing could be performed in such panel form, allbefore singulating the panel into individual circuit board packages.This can simplify handling of components during manufacturing, therebyfurther reducing cost.

FIGS. 2A-6B illustrate an implementation of one particular packageembodiment according to the present disclosure. In this exampleembodiment, the circuit board 202, illustrated in FIGS. 2A-3B, may bepatterned with solder pads 204 configured or patterned to incorporate aVCSEL 206 on one side 208 (e.g., a top side), and a resistor (e.g., atposition 302) and a capacitor (e.g., at position 304), as well as theattachment of wire leads 116 (see FIG. 1A) (e.g., at position 306, 308)on the other side 210 (e.g., a bottom side). However, otherconfigurations, including more or fewer components in differentconfigurations, are possible and suitable. Resistor and capacitor valuesmay vary depending on the VCSEL used and application desired. In theembodiment illustrated, the resistor and capacitor, positioned whereshown, may form a series RC filter in parallel with the VCSEL.

In the illustrated embodiment, the board-based package includes aprinted circuit board (PCB) 202 that is approximately 2 mm in length onat least one edge 212, and in a particular embodiment is approximately 2mm on each edge, and is about 20 mil thick. However, other sizes,shapes, and dimensions than those illustrated are suitable andencompassed by the present disclosure. The PCB 202, in one embodiment,may be a ceramic-filled epoxy board, such as the material identified asRO4350B provided by Rogers Corporation, and may include a wire bondablegold finish. As indicated above, the PCB 202 may include vias 214, suchas copper-filled vias, created through the PCB to connect the VCSEL 206to the PCB core and wire leads. In one embodiment, the vias 214 may beapproximately 4 mil in diameter; however, other dimensions are possibleand suitable.

The VCSEL 206 may be mounted or attached to side 208 of the board 202using any suitable means of attachment, such as a conductive epoxy orusing a solder. In one embodiment, the VCSEL 206 may be mounted orattached to a solder pad 204 on side 208 using a conductive silver epoxyand may be wire bonded to the opposite solder pad on side 208 tocomplete the circuit. The resistor, capacitor, and wire leads, as wellas any other surface mount devices may be soldered to side 210 of theboard 202.

A panel of several circuit board-based packages can be assembledsimultaneously for additional efficiencies. In one embodiment, forexample, the panel may comprise a 4×4 array of packages, and may includescore lines, such as V-score lines, for easier singulation of thepackages. FIGS. 4A and 4B illustrate magnified samples of sides 208 and210 of a package manufactured in an array. In one embodiment, asillustrated in FIGS. 4A and 4B, the panel may include routing 402 aroundsome edges of the individual packages so that they can be broken out of,or otherwise removed from, the panel relatively easily.

A spacer 502, illustrated in FIGS. 5A-5C may be operably coupled orotherwise attached to the PCB 202. While the spacer 502 may be made fromany suitable material, in one embodiment, the spacer may be made from athin sheet of stainless steel, with a specified thickness as required ordesired for the application. The stainless steel sheet may be cutgenerally into a rectangle, and a water jet system or the like may beused to generally form a circular bore hole 506 in the middletherethrough. As indicated above, the spacer 502 may be suitablycoupled, attached, or affixed to the circuit board 202 using anysuitable means for attachment, such as but not limited to, using asolder or an epoxy. In the embodiment illustrated, the spacer 502 may beapproximately 1.9 mm square around the outside edges and include acentral bore hole 506 having a diameter of about 1.2 mm. In oneembodiment, the thickness of the spacer 502 may be about 0.9 mm.However, other sizes and dimensions for the spacer 502 and central borehole 506 may be utilized.

FIG. 6A illustrates a magnified sample of an optical package 200 withthe spacer 502 attached thereto, but without any optical element. FIG.6B illustrates a magnified sample of optical package 200 including anoptical component 602. In one embodiment, the optical component 602 maybe a diffuser, such as a thin film, plastic diffuser. A sheet of thediffuser material may be trimmed into rectangles, or other correspondingshape, slightly smaller than the outer dimensions of the spacer 502, andmounted, diffuser surface toward the VCSEL 206, to the spacer asdescribed above. In some embodiments, x- and y-alignment of the diffuserrelative the VCSEL 206 may not be required. However, it may be desirableto maintain at least a 0.5 mm spacing between the VCSEL 206 and thediffuser 602. In one particular embodiment, the diffuser material may bea 10 mil, polycarbonate diffuser available from Luminit LLC.

The board 202 may be laid out and built by standard board manufacturingprocesses. The resistor and capacitor may attached to the bottom side210 of the board 202, and then the VCSEL 206 may be attached and wirebonded to the top side 208 of the board. The diffuser 602 may beattached using an epoxy to the stainless steel spacer 502, and then thespacer 502 may be attached using epoxy to the board 202. The epoxy usedmay be a biocompatible epoxy, and may be a continuous ring, having nogaps, for preventing leaks. Using a water resistant epoxy may helpcreate a very compact and water tight package for, for example, medicalapplications. With reference back to FIG. 1A, lead or connection wires116 may be soldered to the bottom side 210 of the board 202 to thesolder pads. While any suitable connection wires may be utilized, in oneembodiment, the connection wires 116 may be 38 American wire gauge(AWG), stranded copper wires. The connection wires 116 may be pre-tinnedand pre-bent before attachment to the PCB 202 in array form. In someembodiments, the connection wires 116 may then be configured to exit thearray panel in a direction along the optical axis (i.e., normal to thePCB 202). While one order of steps for manufacturing optical package200, it is recognized that some steps may be eliminated, others added,and/or some steps may be carried out in a different order, all withinthe scope of the present disclosure.

The previous embodiments outline how VCSELs or other optoelectronicdevice could be attached to a panel circuit board, sawn into individualpackages, and then incorporated together with passive optical elementsby adding individual spacers and the passive optical elements. FIGS.7A-10 illustrate an implementation of another particular packageembodiment 700 according to the present disclosure, where generally asecond circuit board layer may be used as the spacer and the separatelayers may be fabricated as an array of packages with, for example,lamination. As illustrated in FIG. 7A-7C, in this example embodiment,again the circuit board 702, illustrated in each of FIGS. 7A-7C, may bepatterned with solder pads 704 configured or patterned to incorporate aVCSEL 706 on one side 708 (e.g., a top side) and the attachment of wireleads 116 (see FIG. 1A) (e.g., at positions 710, 712) on the other side714 (e.g., a bottom side). However, other configurations, including morecomponents, such as but not limited to a resistor and a capacitor, indifferent configurations, are possible and suitable. Any resistor,capacitor, or other component values may vary depending on the VCSELused and application desired. The circuit board 702, which may be a PCB,a ceramic submount, or the like, may be any suitable size and shape. Inone embodiment, however, the circuit board 702 as well as the overallpackage may generally have a hexagonal shape or cross-section, asillustrated in FIGS. 7A-7C. Such hexagonal shape may reduce the packagearea/footprint as well as the maximum diagonal dimension of the package.The circuit board 702, in one embodiment, may be a ceramic-filled epoxyboard, such as the material identified as RO4350B provided by RogersCorporation, and may include a wire bondable gold finish. As illustratedin FIG. 9A, the circuit board 702 may include vias 726, such ascopper-filled vias, created through the circuit board to connect theVCSEL 706 to the circuit board core and wire leads. The vias 726 may beany suitable diameter, as previously indicated.

The VCSEL 706 may be mounted or attached to side 708 of the board 702using any suitable means of attachment, such as a conductive epoxy or asolder. In one embodiment, the VCSEL 706 may be mounted or attached to asolder pad 704 on side 708 using a conductive silver epoxy and may bewire bonded to the opposite solder pad on side 708 to complete thecircuit. The wire leads, as well as any other surface mount devices, maybe soldered to side 714 of the board 702.

Optical package 700 may also include a spacer 716 or spacer layer,illustrated in FIG. 7A, operably coupled or otherwise attached to thecircuit board 702. While the spacer 716 may be made from any suitablematerial, in one embodiment, the spacer layer 716 may be formed from asecond circuit board that is ultimately diced into a hexagonal or otherdesired shape along with the circuit board 702, as will be described infurther detail below. The spacer layer 716 may include a circular borehole 718 in the middle therethrough. As indicated above, the spacerlayer 716 may be suitably coupled, attached, or affixed to circuit board702 using any suitable means for attachment, such as but not limited to,using an epoxy or other adhesive. The spacer layer 716 may be anysuitable thickness and the bore hole 718 may have any suitable diameter,as may be required or desired for the application.

Optical package 700 may further include an optical component 720. In oneembodiment, the optical component 720 may be a diffuser, such as a thinfilm, plastic diffuser. In one embodiment, the optical component 720 maybe formed from a sheet of diffuser material that is ultimately dicedinto a hexagonal or other desired shape along with the circuit board 702and spacer layer 716, as will be described in further detail below. Thediffuser material may be mounted, diffuser surface toward the VCSEL 706,to the spacer using any suitable means of attachment, such as but notlimited to, using an epoxy or other adhesive. In some embodiments, x-and y-alignment of the diffuser relative the VCSEL 706 may not berequired. However, it may be desirable to maintain at least a 0.5 mmspacing between the VCSEL 706 and the diffuser 720. In one particularembodiment, the diffuser material may be a 10 mil, polycarbonatediffuser available from Luminit LLC.

Epoxy or adhesive layers 722, 724 may be provided to affix the circuitboard 702, spacer layer 716, and diffuser (or other optical component)720 to one another, as will be described in further detail below. Insome embodiments, the spacer layer 716 may be pre-deposited with anadhesive film on both the top and bottom surfaces.

As described above, a panel of several circuit board-based packages 700can be assembled simultaneously for additional efficiencies. One method800, but not the only method, of manufacturing a panel or array of suchpackages 700 will now be described with reference to FIGS. 8-11C. Asshown in FIG. 8, at step 802, two circuit board panels and the opticallayer or panel may be first manufactured or otherwise obtained. Asillustrated in FIGS. 9A and 9B, an array 900 of packages 700 may bemanufactured from three separate panel layers 902, 904, and 906 operablyaffixed with one another via epoxy or adhesive layers 908, 910. At step802, a wiring board panel 902 and a spacer circuit board panel 904 mayfirst be manufactured or obtained. These circuit board panels may bemanufactured by conventional circuit board manufacturers using standardtechniques. The wiring board panel 902 and spacer circuit board panel904 may be any suitable size and shape to hold a plurality of circuitboards 702 and corresponding spacers 716 adjacently positioned oneanother. In one embodiment, for example only, a 3″ by 3″ wiring boardpanel 902 may be utilized, and may support about 572 VCSEL submounts 912in an array pattern. However, other sized wiring board panels 902supporting other amounts of VCSEL submounts 912 are within the spiritand scope of the present disclosure. The spacer board panel 904 may begenerally sized and dimensioned to match with the wiring board panel902, and may contain a plurality of bore holes 718 each configured toalign with a corresponding VCSEL submount 912 of the wiring board panel.In one embodiment, the spacer board panel 904 may be pre-deposited withan adhesive film, such as a pressure sensitive adhesive laminate, onboth the top and bottom surfaces, forming the adhesive layers 908, 910.While discussed with respect to being another circuit board layer/panel,the spacer panel could alternatively be a sheet of some material otherthan a circuit board, such as a ceramic or plastic, for instance. Anoptical panel 906 may similarly be provided, generally sized anddimensioned to match with the wiring board panel 902 and spacer boardpanel 904. This panel 906 could be a diffuser sheet, an array of plasticmolded lenses, diffraction gratings, or a sheet of any other suitablepassive optical element(s).

With reference back to FIG. 8, at step 804, a VCSEL 914 may be mountedor attached to one or more, and in most cases each, VCSEL submount 912of the wiring board panel 902. The VCSELs 914 may each be mounted orattached to a first solder pad of a corresponding submount 912, aspreviously described, using any suitable means of attachment, such as aconductive epoxy or a solder and, at step 806, may be wire bonded to theopposite solder pad of the same submount to complete the circuit.

At step 808, if the spacer board panel 904 has been pre-deposited withan adhesive laminate on one or both sides, then likely a protectiveplastic film covers the laminate. Prior to lamination of the separatepanel layers 902, 904, and 906, this protective film or covering may beremoved.

At step 810, the separate panel layers 902, 904, and 906 may be alignedsuch that the plurality of bore holes 718 of the spacer board layer 906are each aligned with a corresponding VCSEL submount 912 and attachedVCSEL 914 of the wiring board panel 902. The optical panel 906 may bealigned such that it covers each bore hole 718. When properly aligned,the panel layers 902, 904, and 906 may be laminated by, for example,placing them in a press, and then into an oven to cure the lamination byboth heat and pressure, resulting in a laminated array of opticalpackages 700.

At step 812, the VCSELs may be burnt-in. In one embodiment, illustratedin FIGS. 10A and 10B, the wiring board panel 902 may be patterned withone or more bus bars 1002, 1004, such as a cathode bus bar 1002 and ananode bus bar 1004, which may be utilized to burn-in any attached VCSELSsimultaneously prior to dicing the array into individual packages.Specifically, as illustrated in FIGS. 10A and 10B, for each VCSELsubmount 912 site, there are two solder/bonding pads 704 illustrated. Inthe embodiment illustrated, the larger of the two pads 704 (referred toherein as the cathode pad) of each VCSEL submount site 912 may beelectrically connected to the cathode of a corresponding VCSEL 914mounted at the submount site. The smaller of the two pads 704 (referredto herein as the anode pad) may be electrically connected to the anodeof the corresponding VCSEL 914 by a wire bond, as described above. Inthe embodiment illustrated, all of the cathode pads within twoneighboring rows may be attached to each other and the cathode bus bar1002, and all of the anodes within two neighboring rows may be attachedto each other and the anode bus bar 1004. The bus bars 1002, 1004 mayinclude corresponding bus pads 1006, 1008. By applying a forward bias tothe VCSELs through the two large bus bar pads 1006, 1008 on either sideof the panel, the VCSELs may be driven with a desired current to performburn-in of the VCSELs. Burn-in could further be performed in an oven,thereby accelerating the VCSEL burn-in process even further.

In other embodiments, burn-in need not be performed at the array level.For example, the wiring board panel 902 could be suitably made withoutthe bus bars 1002, 1004 for burn-in. In this case, the devices could beburned-in at another time, such as at the wafer level or afterseparation into individual packages.

With reference back to FIG. 8, at step 814, the laminated array 900 ofoptical packages 700 may be optionally pre-diced. That is, the arraypanel may be partially sawed through in various directions, toelectrically disconnect the devices from one another. Likewise, at step816, the package devices may be optionally, individually tested, forexample with probe tips placed against the pads 704 of one or more ofthe arrayed packages. The pre-dicing step permits such testing. However,if pre-dicing is not performed, then the packages 700 can be testedindividually after dicing.

At step 818, the laminated array 900 may be diced into singular opticalpackages 700. The array pattern illustrated in FIGS. 9A-10B is for ahexagonal package 700, as described above. In this regard, in oneembodiment, dicing or sawing may be performed in 3 directions (e.g.,along the bus bars and guide lines visible in FIGS. 10A and 10B) to forma generally hexagonal shaped optical package. FIGS. 11A-11C illustratean individually diced optical package 700. Specifically, FIG. 11Aillustrates the top (or diffuser side) of the individually diced opticalpackage 700. The bore hole 718 of the spacer layer 716 may be seenthrough the diffuser surface. FIG. 11B illustrates the bottom side ofthe individually diced optical package. The two bond pads 704 may beconnected, such as through vias 726, to the cathode and anode pads forthe VCSEL 706 (not visible). These are the pads one would probe in orderto test the VCSELs, whether they are still in panel form or separated.FIG. 11C illustrates a side view of the individually diced opticalpackage 700, wherein the 3 separate layers 902, 904, and 906 arevisible.

Although the flowchart of FIG. 8 illustrates a method as a sequentialprocess, many of the operations in the flowchart illustrated herein, orother methods discussed herein, can be performed in parallel orconcurrently. In addition, the order of the method steps illustrated inthe flowchart or described elsewhere herein may be rearranged for someembodiments. Similarly, the methods illustrated in the flow chart ordescribed elsewhere herein could have additional steps not includedtherein or fewer steps than those shown.

While described mainly with respect to an optical package with a singleVCSEL, it is recognized that the package could include more than oneVCSEL or other optical device of the same type or more than one type ofoptical device. Likewise, the package of the present disclosure couldinclude purely electrical integrated circuits that drive or conditionthe signals.

There are a variety of advantages provided by the optical packages ofthe present disclosure. For example, advantages of the optical packagingplatform of the present disclosure may include, but are not limitedto: 1) low cost: in some embodiments, many or all of the packagecomponents may be obtained or manufactured for very low cost, e.g.,pennies apiece for small packages and plastic optics; 2) flexibility:the optical packaging platform of the present disclosure provides agreat deal of flexibility, e.g., off-the-shelf passive opticalcomponents (lenses, diffusers, gratings, polarizers, holographic opticalelements) may be purchased and combined with the active components(VCSELs, LEDs, and photodetectors) merely by fabricating the appropriatespacer; 3) fast prototyping and product development: circuit boards canbe designed and built very quickly, avoiding the much more costly andtime consuming requirements to custom design a package; 4) relativelysimple assembly: a panel of board-based packages can be fabricated andthen fully populated with optoelectronics (e.g., VCSELs), other ICs orpassive electrical components, the spacers, and the optical elements,before singulating the individual boards. It was also observed that theattachment of a metal spacer provided additional thermal management tothe optical packages of the present disclosure. It provided a greaterthermal mass, allowing heat to be radiated away from the packaged moreeffectively. This was observed by monitoring the output power of theVCSEL at various steps of assembly. The VCSEL is sensitive totemperature, with output power dropping off as temperature rises. Whenthe spacer was attached to the packaged, the VCSEL output powerimproved, indicating an improvement in heat removal from the packages.

As used herein, the terms “substantially” or “generally” refer to thecomplete or nearly complete extent or degree of an action,characteristic, property, state, structure, item, or result. Forexample, an object that is “substantially” or “generally” enclosed wouldmean that the object is either completely enclosed or nearly completelyenclosed. The exact allowable degree of deviation from absolutecompleteness may in some cases depend on the specific context. However,generally speaking, the nearness of completion will be so as to havegenerally the same overall result as if absolute and total completionwere obtained. The use of “substantially” or “generally” is equallyapplicable when used in a negative connotation to refer to the completeor near complete lack of an action, characteristic, property, state,structure, item, or result. For example, an element, combination,embodiment, or composition that is “substantially free of” or “generallyfree of” an ingredient or element may still actually contain such itemas long as there is generally no measurable effect thereof.

In the foregoing description various embodiments of the presentdisclosure have been presented for the purpose of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise form disclosed. Obvious modifications orvariations are possible in light of the above teachings. The variousembodiments were chosen and described to provide the best illustrationof the principals of the disclosure and their practical application, andto enable one of ordinary skill in the art to utilize the variousembodiments with various modifications as are suited to the particularuse contemplated. All such modifications and variations are within thescope of the present disclosure as determined by the appended claimswhen interpreted in accordance with the breadth they are fairly,legally, and equitably entitled.

1-11. (canceled)
 12. An array of optical packages comprising: a firstcircuit board panel comprising a plurality of vertical-cavitysurface-emitting laser (VCSEL) submounts each configured for mounting aVCSEL thereto; a second circuit board panel comprising a plurality ofbore holes therethrough, the second circuit board panel being shaped anddimensioned to align with the first circuit board panel such that theplurality of bore holes align with the plurality of VCSEL submounts; andan optical panel comprising a sheet of optic-altering material, theoptical panel being shaped and dimensioned to align with the secondcircuit board panel such that the sheet covers the plurality of boreholes.
 13. The array of optical packages of claim 12, wherein the firstcircuit board panel comprises a printed circuit board (PCB).
 14. Thearray of optical packages of claim 13, wherein the second circuit boardpanel is affixed, on a first side thereof, to the first circuit boardpanel.
 15. The array of optical packages of claim 14, wherein the secondcircuit board panel is affixed, on a second side thereof, to the opticalpanel.
 16. The array of optical packages of claim 15, wherein the secondcircuit board panel is coated on the first and second sides thereof withan adhesive laminate for affixing the second circuit board panel to thefirst circuit board panel and the optical panel by lamination.
 17. Thearray of optical packages of claim 16, further comprising a VCSELmounted to each of the plurality of VCSEL submounts.
 18. The array ofoptical packages of claim 17, wherein the optical panel comprises asheet of light diffusing material.
 19. A method of making an opticalpackage comprising: attaching a plurality of vertical-cavitysurface-emitting lasers (VCSELs) to a first circuit board panelcomprising a plurality of VCSEL submounts, each configured for receivinga VCSEL; aligning a second circuit board panel with the first circuitboard panel, the second circuit board panel comprising a plurality ofbore holes therethrough and being aligned with the first circuit boardpanel such that the plurality of bore holes align with the plurality ofmounted VCSELs; aligning an optical panel with the second circuit boardpanel, the optical panel comprising a sheet of optic-altering materialand being aligned with the second circuit board panel such that thesheet covers the plurality of bore holes; and laminating the firstcircuit board panel, second circuit board panel, and optical paneltogether.
 20. The method of claim 19, further comprising dicing thelaminated panels into singular optical packages, each optical packagecomprising a VCSEL aligned with a bore hole and configured to emit alaser beam through the optic-altering material of the optical panel.